1. Field of the Invention
The present invention relates to apparatus and techniques used to shield sensitive electronic components from the deleterious effects of static electricity. More specifically, the present invention relates to apparatus used to seal bags used to shield and handle such sensitive electronic components.
While the present invention is described herein with reference to a specific embodiment in a particular application, those having ordinary skill in the art and access to the teachings of the present invention will recognize additional modifications and embodiments within the scope thereof.
2. Description of the Related Art
The harmful effects of static electricity on sensitive electronic components is now clearly recognized. In response to a serious need to mitigate this source of component failure, numerous elaborate procedural safeguards have been adopted. For example, since most of the exposure to electrostatic discharge (ESD) occurs during the human handling of the components, one procedure requires the worker to wear a wrist strap which is electrically connected to a workbench which in turn is grounded. In apparent recognition of the severity of the problem, wriststraps are typically tested at least daily.
In these special areas where ESD cannot be tolerated, other safeguards are used as well including the handling of electronic components in special bags, boxes and etc.. These devices have particular electrostatic properties consistent with the restrictions of the controlled environment within which the handling is to take place. For example, while a conductive shield may be preferred for ESD reasons, state of the art materials such as conductive foam may not be suitable in say a clean room where fibers or other emmissions may comtaminate the controlled atmosphere.
A particular problem exists with the ESD bags currently in use. That is, the bags (typically made of an anti-static plastic and coated with a metal such as nickel) must be closed or a charge from the hands of the worker will migrate from the surface of the bag into the interior and onto the static sensitive component.
Prior art techniques for closing the bags include the use of stickers and plastic anti-static snap-sticks. A sticker is simply a tag with an adhesive backing which is used to attach the open end of the bag to the bag surface. Two principal problems in using the sticker have lead to the use of the snap-sticks: one is that as the sticker is removed, an electrostatic charge is often developed and the other is that the sticker blocks vision into the otherwise typically transparent bag. This necessitates additional handling of the bag and presents additional opportunities for ESD contamination.
The snap-stick is a closure made of an anti-static plastic which folds at its middle so that its ends may be snapped together. Thus, the snap-stick is used to snap the open end of the bag shut. Unfortunately, the use of the snap-stick has been found to be problematic in that the procedure of opening the snap has been of such difficulty as to cause an annoying injury to the fingernails of the bag handler. This has the effect of discouraging the use of the bag and the concomitant undesireable effects on production and costs.
Accordingly, there is a need in the art to provide a means for closing ESD bags which is simple and easy to use and which does not cause injury or discomfort to the bag handler.